Sudden peak in water levels caused by unusually high rainfall

Vientiane, Lao PDR, 25 Dec 2013

The Mekong River’s water levels had increased during the period of December 15-21, with a rise of over one metre in the mainstream. For example, further upstream of Vientiane, Lao PDR the rise in water levels was seen in Chiang Saen District of Chiang Rai Province in northern Thailand, rising from 4 metres to 6.5 metres between the 15th to the 17th of December 2013. Water levels at the Pak Beng water monitoring station in Lao PDR increased from 7.7 metre on the 14th to 17.2 metre on the 17th, representing an almost 10-metre rise in three days.

Preliminary analysis of the Mekong River Commission’s data reveals that the sudden rises are the results of unusually high levels of rainfall in northern Lao PDR and north-eastern Myanmar and southern Yunnan province in China. Estimates suggest that some areas received in excess of 120 millimetres in just two days. This caused a rapid rise in many tributaries of the Mekong and resulted in a rapid peak in the mainstream. The MRC’s past records show that there had not been such a sudden peak of this scale in December in the last 50 years. However, there is no evidence suggesting that the sudden peak was caused by unusual releases of water from the dams in China.

The water levels in the Mekong have been dropping from those levels seen in the last week’s rises.

During the dry season the MRC provides a weekly update on water levels observed in the past week and water levels forecasted for the upcoming week at 22 water monitoring stations on the Mekong mainstream. The information is provided on the MRC's website; www.mrcmekong.org and its flood forecasting website; http://ffw.mrcmekong.org.